There is a now small herd of wild horses that roam the island (particularly avoid the area populated by harpies). They don't get close to the city often, but they don't run away from Islanders who approach them. Rather tame for wild horses...

And Islanders will find themselves drawn to the horses if they get too close. So drawn to them, they will have the insatiable need to remove as much of their clothes as possible and ride one. The effects will last for up to two hours or with the completion of an auspicious act.